This proposal is for permission on a "compassinate use" basis to administer rhSODI intrathecally via an in-dwelling pump to two patients with familial ALS arising from mutations in cytosolic Cu/Zn superoxide dismutase. It will test the hypothesis that an increase in CSF SODI to two-fold above normal will slow the course of the illness as measured over 8 - 12 weeks with quantitative neuromuscular function testing.